Service line with rupturable connector



March-7, 1950 G. L WHITMAN ET AL 2,499,709

SERVICE LINE WITH RUPTURABLE CONNECTOR Filed April 19, 1946 Y 2 Sheets-Sheet l I N VEN TORS Georqe L. Wh/'marl and Percy F. Shari ATTORNEY I MalCh 7, 1950 G. L. WHITMAN ET AL 2,499,709

SERVICE LINE WITH RUPTURABLE CONNECTOR Filed April 19, 1946 2 Sheets-Sheet 2 44 45 4o 4| 4 ma Il,

' NVENTORS Georqe L. W/v/' and Percy F. 5/1

ATTORNEY Patented Mar. 7, 1950 QFFICE SERVICE LINE WITH RUPTURABLE CONNECTOR George L. Whitman and Percy F. Short, Weedsport, N. Y.

Application April 19, 1946, Serial No. 663,382

6 Claims. 1

The invention relates to improvements in service lines of electricity transmitting systems.

In electricity transmitting systems, it is cornrnon practice to tap customers service lines to power transmission lines, the power transmission lines being supported at intervals on poles, and each service line being anchored to and suspended in the air between a building to be served and a pole supporting the power lines and also being electrically connected with a power line and a line extending into the building to be served. Such overhead or exposed service lines are frequently subjected to abnormal stresses which either break the lines, tear them from one or the other of their two anchorages, or tear away a part of a customers building to which the service line is anchored. Such stresses may be caused, for example, by high winds, by accumulation of snow, sleet or ice on the service line, or by the line being struck by a falling tree or tree limb. When a service line is broken, or is torn away from a building, property damage and loss of service are the usual results, and frequently also a live or charged end or part of the broken service line is grounded with resultant life and fire hazards. Furthermore, repair of such broken service lines requires a considerable expenditure of time of skilled linemen, and these linemen usually cannot repair a service line installation when the line has carried away a part of a building to which it was anchored. In the latter case, the building must first be repaired to restore the building anchorage of the service line.

The present invention has for its general purpose the provision of a service line for electricity transmitting systems of the kind set forth which, while the line will break under abnormal stress, avoids the disadvantages above pointed out and may be quickly and easily restored to service.

Further purposes of the invention are to provide a Service line for use in systems of the kind above set forth so constructed that the service line will be disconnected from a power transmission line at a predetermined point close to a pole which supports both lines, and to provide a service line having a separable and easily re-connectible joint therein which is closer to one of two suspending anchorages of the line than said anchorage is to the ground, said connection being separable by abnormal stress or pull on the service line between the suspending anchorages of the service line.

Another purpose of the invention is to provide in a system of the kind set forth superposed service lines connecting transmission lines with a building to be served and designed to rupture under abnormal stress and at a predetermined point conveniently reachable from a transmission line supporting pole with successive ones of the superposed service lines designed to rupture at diierent distances from the pole.

A further purpose of the invention is to provide a service line for systems of the kind set forth having between its pole and building anchorages a splicing means held connected by a shear pin.

Other purposes and advantages of the invention will appear from the following description of illustrative embodiments of the invention shown in the accompanying drawings.

In the drawings:

Figure 1 is a fragmentary perspective view illustrating one embodiment of the invention;

Figure 2 is a detail sectional view showing the safety splice employed in the service lines shown in Figure 1;

Figure 3 is an exploded perspective View showing the tap connection between each service line and the associated line extending into the buildlng;

Figure 4 is a detail perspective view showing one of the service lines and power transmission lines of Figure 1 and their connections with each other and a pole supported insulator;

Figure 5 is a top plan view (partly in section) showing a modied construction; and

Figure 6 is a detail perspective View of certain of the parts shown in Figure 5.

The construction shown in Figures l to 4 will rst be described.

The service lines i6, two of which are shown, extend between insulators held respectively to the upper part of a building to be served and the upper part of a power transmission line supporting pole, one vertical side of the building being designated Il, the adjacent roof portion of the building being designated l2, and the power line supporting pole being designated I3. The power transmission lines M, two of which are shown, are, as is common, secondary power lines supported by a line of poles, including the pole I3 shown, and connected in known manner through transformers (not shown) with primary power lines (not shown) also supported by the line of poles. Leading from the building are the usual insulated circuit wires or lines i5, two of which are shown. The service and power lines shown in this embodiment of the invention are insulated wires or wire cables and form with J the insulated wires I5 parts of a transmission system or circuit of the two-wire type.

The anchorages of lines I 4 to pole I3, the anchorages of lines IIB to the building and pole, and the tap connections of lines Ill with lines I4 and I5 shown are all well known, and may be varied. if desired. in accordance with known practices, and need be only briefly described.

The known insulator supporting bracket l5 is fastened to the upper portion of pole I3 by suitable fastening devices Il and supports between its horizontally extending arms the. two known spool-like insulators I8 which are removably held in place one above the other as is usual by the known headed metal pin I9 which extends through the axial bores of the insulators and through registering holes in the arms of the bracket. Each power transmission line Ill is held to a diierent one of the insulators I8 in known manner, a short length of insulated wire 2E being for this purpose bent around theA insulator and its'ends twisted spirally around the power,- line I4A at opposite sides'of the insulator, as is common in the art. Each Servicel line or wire Il) vis anchored to a diiierent one of the insulators il!y by passing the wire about the insulator between the heads of the latter and twisting thewire upon itself as shown at ia adjacent the insulator, leaving' an endportion of the wire for tapping to the adiacent power line.

Anchored to anA elevated portion ci:` the side I I of the. building, one directly under the otherY as is common in the art; are two, known insulators 2l for suspending' the service lines between the building and the insulators I8 on` pole i3; As shown, these insulators are of the knownv kind having screw threaded metal stems Zia screwed into the building structure adjacent the. roof of the building, and also having an eye for passage' of a service line through the insulator. The service lines are anchored, as' usual, to different ones of the insulators 2| by passing Athe service line through the insulator eye and `twisting the adjacent end portion of the lineA about theY suspended main stretch or the line adjacent the insulator as shown at Illb. Theservice lines thus extend one below the other. between their anchorages.

Adjacent the pole I3, one end of* one ofthe service lines is tapped to one of the power'trans'- mission lines and one endY of the other' service line is tapped to theother-power transmission'V line,A as is usual in the art; Adjacent the building', one end of one of the lines'I' is tapped toone-orthe service lines, and one end of the'other line I5l is tapped to the other service line, 'as is vusual in the art. Any known line tapping connectionsmay-be employed. As shown in Figures l and 3, a bared portion I5@ of each insulated wire I- is clamped to a short bared length Iof its associatedinsulated service line or wire, at a point close to the service line anchoring' insulator 2| by a known form of all-metal clamping device comprising a slotted bolt 22, a nut 23 and a wire clampingblock Mythe block 24 being slidable inthe slot in the bolt andbeing held to the nutfor rotation' of' the nut aboutv the block. Adjacent pole I3' a bared end portion llld of each insulated service wire is clamped. by one of the clampingd'evices 23e-2"'- 2li to a short bared length4 Illa of its associated insulated power line III, as shown in. Figures 1 and (l.

The improvements in the foregoing known transmission system now. will be described.

According to the present invention, each service line of the transmission system is so constructed that, when subjected to abnormal tension or breaking stress between its points of anchorage to a transmission line supporting pole and to a building to be served, the service line will break between said anchorage points at a predetermined selected, point Very close to the anchorage of the service line to the pole.. The distance from the pole to the selected breakage point is kept as short as possible, preferably from a few inches to a maximum of one yard, so that the ruptured service line may easily be reconnected by a lineman from the pole and also so that, when the line breaks a long dead end thereof will drop to the ground and a very short live end thereof will be sustained from the pole out of contact with the ground. In a transmission system with overhead power and service lines, the improved service lines will each rupture under abnormal stress, but at such a selected point that a broken service lineVv may easily be repaired by a single lineman, short circuits and re hazards are avoided', grounded'v live wires' are` avoided, andthe service line'will break under abnormalstresswithout damaging the building from'which it is suspended. The distance between` the selected breakage point of the service line and Athe'anchorage of said lineto the transmission line supportingpole I3` must bevv less than the distan'cebetween said anchorage andV the* ground',l the latter distance commonlyL being several yards or more foroverhead clearancefor traiiic'.

While the weakening of thev service' line at a selected point for rupture thereat under abnormal stress may be eected` in various ways,y it is preferred and highlyV desirable that the line beso constructed that a single lineman may easily and 1 tollv are' eaclrpreferably` constructed as'willfnow be'describe'd';

Close to the power lineesupporti'ngpole` anchorage` of the service'line; and? preferably' within the limits above set forth, the long stretch of the service line between said poleanchorage' and't-he building anclioragev of 'said =linehas introduced therein an electricity1 conducting splice vwhi'clrwili break under astress'substantia-lly less` than that required to` break theservice'lineat any other point between itsanchorages andi, preferably, will break without yaffecting the service line anchorages".

This splice connects twobared and separated portions *Ille and IIlfoi thesinsulated' service lineand comprises twov conductive met-al shells-25- and 26 separably' joined by a metallic shear pin 2l and each provided with conductivem'eans for gripping a diierent oneI of said' service line por'- tions I-Ile and IIlf'. At their "adjacent ends, the' shells 25A and- 26:- 'areformed respectively withl a tubular metal sleeve portion' 28s of rectangular cross-section andv a metal plug portion 29" of' similar cross-section telescopically and'rem'ovably inserted in said'sle'eve' portion.. Portions' 28'and 29'are provided'y with registrable` holesthrough which the shear pin 21 extends to tie the shells together, the pin having its ends bent as shown to prevent accidental disengagement of the pin from the sleeve and plug portions, The shells and said sleeve and plug portions thereof are formed of suitable strong and corrosion resistant metal of good electricity conductivity such as hard copper or brass and the shear pin is of small cross-section and formed of a cprrosion resistant metal of good conductivity but of substantially less shear resistance than the service line wire and shells, such metal for the shear pin preferably being aluminum or soft copper. The small cross-section of the pin will, however, alone provide a localized point of weakness in the service line.

While the bared portions Ie and If of the service line may be connected in various ways with the shells 25 and 25, it is preferred to provide each shell with a known type of wire-end gripping means shown in Figure 2. Said gripping means will be only briefly described. Each shell is provided at its outer end with an axial bore 30 through which a bared end of the service line is slidably insertive, and each shell is provided with a frusto-conical chamber 3| tapering toward bore 3U. Housed in each said chamber and extending longitudinally thereof is a set of bar-like gripping jaws 32, the inner ends of which extend loosely through radial jaw spacing slots 33 in a disk-like spacer 34 slidable facewise thereof in chamber 3|. Jaws 32 are formed of metal of the kind above set forth in describing the shells 25 and 26.

At their inner ends, the jaws in each shell are engaged by one end of a helical expansion spring 35 `which urges the jaws toward the smaller end of chamber 3! to contract the set of jaws on the bared wire end to grip and hold the wire end. The other end of spring 35 abuts a disk-like abutment 3E which the spring 35 holds-pressed against a contracted portion of the shell adjacent the inner end of the shell. The jaws are serrated across their inner wire-engaging faces. Preferably, each shell is formed with an internal annular rib 31 engageable by the outer ends of the jaws to limit projection of the jaws by the spring. The plug portion 29 of shell 26 may be formed integrally with, or otherwise fixed to, said shell. In the construction shown, the plug portion 29 and the body of shell 26 are welded together. When a service wire end is inserted in the shell, the set of jaws will open to receive the wire end, but pull tending to withdraw the inserted wire end, and the action of spring 35 on the jaws will cause the set of jaws to grip and hold the wire end against withdrawal from the shell. Each shell may be provided with a longitudinal slot 38 for insertion of a tool to compress the spring to release the grip of the jaws on the inserted wire end.

The modified embodiment of the invention shown in Figures and 6 now will be described. In this embodiment, the construction is the same as that described in Figures 1 to 4, except as now will be pointed out. In the modied embodiment, the shell 26 and that part of the service line gripped thereby and anchored to insulator I8 and tapped to the associated power line I4 are omitted, and the following described parts are substituted therefor to form part of the service line.

A metal bar or plug 39 of rectangular crosssection similar to that of plug portion 29 is held at one end in socket portion 28 of the Wire grip- 6 ping device 25 by the shear pin 21, and said device is attached to the major stretch of service line wire l0 as in the embodiment of -Figures 1 to 4. A resilient and divided metal ring or clip t6 embraces insulator I3 between the heads of the insulator and is formed at its ends with two substantially parallel ears 40a between which the other end of the bar or plug 39 is clamped by a bolt Ill and a nut 42 threaded on the bolt, thus providing a stretch of service line anchored to the building and to the adjacent transmission line supporting pole. To continue this service line to its associated power transmission line I4, .there is provided a short length of insulated wire 43 having bared end portions i3a and 431 clamped respectively to bar 39, between the connections of said bar with shell 25 and clip 49, and to the bared portion Ma of a power transmission line I4 by clamping devices 22-23-24 of the kind heretofore described. Bar 39 is provided with bores 44 and 45 to receive respectively the shear pin and the bolt. The metal clip 49 from one to the other of its ears is preferably curved transversely, as shown, to fit closely about the usual concave surface of the stem portion of the known insulator i8, and said clip is formed of strong and corrosion resistant metal adapted to withstand stresses which will rupture the shear pin.

As shown in Figure 1, in multiple wire circuits, the rupturable splices interposed in the superposed service lines leading to a customers building are so staggered from service line to service line that upon rupture of a line, the live end thereof cannot touch a splice or bared portion of another service line of the superposed series of lines. Preferably, the splices are stepped as shown with the splice of the uppermost service line closest to the service line anchoring insulators on pole I3.

We claim:

l. An electricity transmitting system of the kind including a pole-supported power transmission line, and a service line tapped to said transmission line adjacent a supporting pole for said transmission line and having an anchorage to said pole and an anchorage to a support remote from said pole suspending said service line above ground between said anchorages, characterized by the service line comprising two line sections extending toward each other from said anchorages, and means connecting said sections of the suspended service line and separable by abnormal stress imposed on the service line between said anchorages, said connecting means being located closer to the pole anchorage of the service line than the distance between said anchorage and the ground.

2. An electricity transmitting system, as claimed in claim 1, wherein said connecting means comprises two telescopically interfitted metal elem-ents each positively mechanically secured to and in electricity transmitting connection with a different one of said service line sections, and a shear pin separably holding said elements in telescopic engagement.

3. In an electricity transmitting system of the kind in which a line of poles supports a plurality of power transmission lines to which are tapped service lines which extend away from the transmission lines, the improved service line installation which comprises a plurality of service lines anchored one below the other to one pole of said line of poles above ground and each tapped to a different one of said transmission lines, means anchoring said service lines above ground and one :below the other remote from .said pole :and suspendingsaidj lines vin superposed relation between'their anchorages, each'service line'haw ing introduced therein ata selected point between its anchorages arupturable joint `of lessv strength than the Yremainder offthe anchoredstretch of the line, said `jointsvin .the servicerlinesbeing all located closer to the pole'anchorages-oi the lines than said anchorages are-to the ground, said service linejoints beinglocated'diiferent distances from the poleand progressivelyV staggered outward fromihe pole from the uppermost tothe lowermostfones ofthe service lines.y

4; An soverhead electricity transmission system of the :class wherein there is tapped toa power transmission line azservice line which extends out of doors and'above ground between two anchoragesforfsaidline vone of which is xedto one of aseries of spaced ground engaged supports which support the power transmission line `at intervals therealong jout of doors anda-bovesground, characterized by said` service line comprising two line sections which extend toward each other from different ones of said anchorages, and la line weakening splice which electrically connects and positively mechanically joins said two line'sections at a point which is within' convenient reach of-a lineman fromsaid one of said power transmission line supports and is closer to that one of said service line anchorages which is fixed to said support than said anchorage is toA the ground.A

5. In adeviceY of the class described, the com; bination of, astreet pole, a supporting bracket carried thereby spaced' upwardly aboveT the ground, anv overheadelectric powerlline, a lead-in conductor having one end secured -to Vthe bracket y and connected electrically to the power line to take current from the same, means supporting the other end of the conductor normallyA to hold the conductoroff the ground, said conductor being in two lengths, the length supported `from the bracket `and:'fattached to thek .power :line being VAof less length than the distancebetween the bracket and ithe ground,` wherebysaid length whenfall-r ing iromthe'bracket cannot reach the ground, and a connectorof thevmechanical overload releasef type normally coupling togetherl the adjacent ends ofthetwo lengths of conductor.

6. A leadeinconductor for use in. tapping ofi electric currentirom a street power line,4 said conductor provided at onev end with means'for supporting said endand for connecting the same tothe :powerline'and including ,a coupling of the mechanical overload release A.type `located closely adjacent said supportingv means,` said. coupling beingV of conductive material normally maintaining an electric path therethrough andresponsive to an axialv pull on .the conductor materially in excess of its weight to' cause the component parts of the 'coupling to separate and `thus'zperrnit the balance of-theconductor beyond the coupling-to fall free from and 'thus becorneindependent of the `power lineand lde-energized.

GEORGE L. WHITMAN. PERCY F. SHORT.

REFERENCES erran- Tlie-'following"references are of record'in the filer-of this -patentt UNITED ,l STATES. PATENTS Number NameA Date 7353839 Stiles f Aug. 11, 1903 980,341 Roper Jan. 3, 1911 1,517,602 Trogner Y Dec. 2, 1924 2,019,149'. Mack" Oct. 29, 1935 2,166,458' Berndtv i July 18, 1939 2,309,041 Bookeret al.` 1 Jan. 19, 1943 FOREIGN PATENTS Number. Countryw Date 17,316=- Sweden .i v.Mar. 26,' v1904 445,941 GreatBritain 1936 

